We're proud to announce the release of yt version 1.6, a point release of the analysis and visualization toolkit for Adaptive Mesh Refinement data. This release contains many small improvements to the codebase, as well as several large improvements. Most prominently, it features a completely redesigned, massively parallel implementation of the halo finding algorithm HOP, as well as attendant improvements to particle data IO and parallel communication. Additionally, the underlying data structures for hierarchical datasets have been rewritten for speed and clarity, enabling the future addition of new multi-resolution data formats to be easily added. yt features native support for Enzo (http://lca.ucsd.edu/projects/enzo) data, providing a natural and intuitive way to address physical regions in space as well as processed data. Some of the changes since yt-1.5 (released on November 3, 2009) include: * (New) Parallel HOP ( http://arxiv.org/abs/1001.3411 ) * (Beta!) Software ray casting and volume rendering (Sam Skillman has a gallery here: http://casa.colorado.edu/~skillman/simulation_gallery/simulation_gallery.htm... ) * Rewritten, faster and better contouring engine for clump identification * Spectral Energy Distribution calculation for stellar populations * Optimized data structures such as the hierarchy * Star particle analysis routines * Halo mass function routines * Completely rewritten, massively faster and more memory efficient Particle IO * Fixes for plots, including normalized phase plots * Better collective communication in parallel routines * Consolidation of optimized C routines into amr_utils * Many bug fixes and minor optimizations * Installation instructions, documentation, recipes, mailing list info and assorted other items can be found at the website, http://yt.enzotools.org/ along with an annotated changelog at http://yt.enzotools.org/doc/changelog.html . yt is a Free and Open Source project, and we invite you to get involved. For more information, join the yt-dev mailing list, or see the hacking guidelines on the Wiki: http://yt.enzotools.org/wiki/HackingGuidelines . Sincerely, The yt development team: Matthew Turk Stephen Skory Britton Smith Jeff Oishi Sam Skillman Devin Silvia John Wise David Collins